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Panarea Apr. zo, 194s` UNITED STATES PATENT vOFFICE y 2.43am j Y maarcLu'rcn can Wesley Porter, Alexandria. vn. Appucauon December z, 1942,serial No. 461,659

s claims. (camz-30.5) l

(Granted under the act of March 3, 18783, as

The invention herein disclosed is ameans Ior increasing the speed andpersonal safety and reducing manual fatigue of the operator in drivingnuts` or other rotarily wedged parts into place or loosening themtherefrom after they have been tightened.

The main object of the invention'is to adapt the use of power means forsupplying both intering intermittent impulses thereto, and vice versa.,

said means being operative automatically upon increase in resistingtorque due to tightening of the nut or decrease in the resisting torquedue to loosening thereof, respectively, the change-over being effectedat a torque value in accordance with the speed of the power motor, saidmeans -iurther automatically increasing the energy supplied per impulseduring intermittent operation as well as increasing the number ofimpulses upon increase in speed of rotation of the power motor.

In the accompanying drawings, two preferred forms of my invention areshown as arrangement A, and arrangement B. Figs. 1 to 5 illustratearrangement A and Figs. 6 to 9 illus- In'the drawings:

Fig.v 1 is an elevation of an assembly of the wrench according toarrangement A, illustrating its application to a nut. and cut away toshow Y the principal parts of the invention.

. arrangement "B," illustrating its application to a nut. and cut awayto show the principal parts of the invention,

Fig. 'Z is a transverse cross-section taken at the section line 1-1 ofFig. 6, l

Fig. 8 is a transverse cross-sectionof the torque block I taken at thesection line 8-8 of Fig. 6,

amended April 30, 1928; 370 0. G. 757) Fig. 9 is a transversecross-section taken at section line 9.9 of Fig. 6.

It is my aim to provide an impact wrench attachable to a source ci power(electricor corn-y pressed air) and so operable therefrom that this`wrench may through its component parts, be used to impart blows orimpacts to a nut in Vsuch a way as to turn or rotate the nutfortightening or loosening purposes.

I-t 1s i'urther my aim to combine in this same tool, means for' simplehigh-speed spinning, of nuts on or oi! bolts, whenever the nut ts looseenough to permit such operation.

The advantages of this wrench over other tools for this purpose are itscompactness. simplicity. effectiveness, eiciency, safety. smoothness ofoperation, speed and lack of fatigue with which my wrench can beoperated.V

Operation "A Referring to arrangement "A," Figs. 1 to S on E splines 1.1, etc., engaging impact. transmtting rolling elements 8, 8, etc., suchas balls orl the like, and driving them. 9, 9, etc., are splines in thetorque block concentrically placed with reference to splines 1. 1, etc.,and are so placed as to engage and be impacted by the balls 8, 8, etc.

I0 is a square projective end-post on the impacter5.

II is a disc for place. I2 is a square hole in II for tting over thesquare end-post I0. I3 is a coupling or sleeve, I4 being a square holerunning axially through the center of sleeve I3. I5 is a squareprojective end-post on drive shaft I6 for driving` the impacter 5 bycommon engagement there` with by means of sleeve I3 and end-post III.

I1 is the casing enclosing the various parts as shown and forming partof the body of the assembly. I8 is a bail bearing assembly shown forillustrative purposes, it being recognized that the bearing details andactual location are subjectV to variation.`

I9 is the casing or body of the motor which drives the rotating parts ofthe tool. wrench handle. 2l is the motor operating trigger remainingbans s, s, etc., m'

20 is the Y or switch, 22 is a. hose orcaible connection. these partsbeing shown for illustrative purposes only. 23 is a flange on the casingI9, 24 is its companion on casing I1. 25, 25, etc., are assembly bolts,and 26 is a spacer between anges 23 and 2l. 21 is a socket wrench and 28any nut it is desired to turn on any bolt 29 holding some part 30 to anyother part.

The operation of my device is as follows: Referring to Fig. 1 andassuming 28 is a nut which it is desired to turn on bolt 29, and thatthe wrench is attached to a source of power as at 22, the operator mayselect the proper size socket wrench 21 and piace it on the projectiveend-post 3 and then engage wrench 21 with nut 28. Then,

by pressing the trigger 2| the motor will start up and revolve driveshaft I8, and consequently the impacter 5, this part being positivelyengaged with shaft I8 through end-post I5, sleeve I3-and end-post I8.Referring to Fig. 2 assume balls 8. 8, etc., are at the bottom of theopenings between splines 1, 1, etc., i. e., nearest the axis of rotationof the impacter 5. As soon as the impacter comes up to a certain speed,balls 8, 8, etc., will be thrown outward by centrifugal force until theydrop into the slots between splines 9, 9, etc., in the torque block.However, the balls cannot get out of reach of splines 1, 1, etc., andwill therefore be driven in a circular path inside the torque blockuntil they impact splines 8, 9, etc. At this instant the balls are inshear between splines 1, 1, etc., and splines 9, 9, etc. The Wedgingaction thus produced on the balls will, due to their position withrelation to the respective splines, force the balls back toward thecenter of rotation, and thus out of engagement with splines 9, 9, etc.,whereupon 5 will regain anyspeed lost and above cycle of events will berepeated. This cycle will be repeated at a rate depending on the speedof the driving motor. A major part of the force of impact of the ballswith the splines 9, 9, etc., will be transmitted through the torqueblock to the wrench and the nut 28, which will be broken loose if it isfrozen and rotated. The looser the nut becomes, the faster it will bedriven, iinally approaching the speed of the driving motor.

The nut 28 may be turned in a direction opposite to that above describedsimply by reversing the motor.

The depth of the grooves formed by the splines 9 on the outer members isless than the radius of the balls '8, whereas the depth of the groovesformed by the splines 1 on the inner member is slightly greater than thediameter of the balls 8. The edges of the splines 1 on the inner memberare formed with sharp squared corners against which the balls 8 will bewedged at the time of impact.

Arrangement "B The aims as set forth above apply for arrangement B, andin addition thereto it is my aim to provide in arrangement B a means formore positively locking the driving and driven members of the wrenchtogether in order to cause the driven member to rotate at the same speedas the driving member without impacts, whenever the nut being turned islose enough to permit. It is further my aim to provide a means forcausing the change-over from impacting the nut to full speed rotation ofthe nut and vice versa automatically.

The advantages of arrangement B are the same as mentioned above, and inaddition thel'eto, the positive locking feature of arrangement B has thefurther advantage of greater speed and emciency under certain operatingconditions.

Referring to arrangement "B." Figs. 6 to 9 on the accompanying drawings,I is a cylindrical torque block; 2 is a cylindrical impacter or balidriver; 3, 8, etc., are impact transmitting balls;

l, 4, etc., are slots or pockets in the impacter 2 for holding andcarrying the balls: 5, 5, etc., are companion slots or pockets in thetorque block for receiving the balls; 6 is a cylindrical bore in thetorque block of smaller diameter than 1 which is also a cylindrical borein I. The centers of both bores coincide with the center of rotation ofthe torque block and the impacter. 8 is a square hole in the torqueblock, centrally located in the outer end thereof. 9 is a cylindricalbearing surface at the outer end of the torque block. I8 is a squareprojective end-post of socket wrench I I, and serves to engage thetorque block positively in the square hole 8 and is a snug nt therein.I2 is any nut to be turned, and is shown for illustrative purposes only.

I3 is the greater cylindrical section of the impacter 2, being ofslightly smaller'diameter than bore 1 for clearance. I4 is the greatercylindrical section of the torque block. I5 is a square endsection ofdrive or motor shaft I6. I 1 is a shoulder or collar on shaft I8,forming the inner seat for coil spring I8, I9 being the outer seat whichis freely slidable axially on section I5. 2l) is a square hole centeredaxially through the impacter for engaging section I5, making theimpacter freely slidable axially on said section.

2i is the outer casing of the assembly of parts as shown, and forms partof the body of the wrench. 22 is the motor casing or frame. havinghandle, power attachment, trigger, etc., as 20, 22 and 2i in arrangementA," Fig. l. 23, 23, etc., are bores for receiving assembly bolts like 25in arrangement A, Fig. 1; 24 and 25 are bearing assemblies shown forillustration, possible variation in their details and locations beingrecognized. 28 is a grease packing and dirt seal.

29 is any bolt engaged with nui-I I2 for the purpose of holding any part30 to any other part, these parts being shown for illustrative purposes.

The operation of arrangement B of my invention isas follows: Assumingthat the tool is attached to a source of power, and the socket wrench IIis in place on nut I2, the operator may press the trigger and start themotor, whereupon shaft IG will be rotated, and consequently the impacter2. Spring I8 and seat I9 will likewise be rotated. If the nut I2 resiststurning sumciently, wrench II and consequently torque block I willresist also.

At this point halls 3, 3, etc., will be in shear between the opposingedges of the slots or grooves l, I, etc., and 5. 5, etc., and there willbe a wedging action set up by the balls being forced out of grooves 5,5, etc. Consequently, the impacter will slide on section I5 away fromthe torque block I. and seat I9 will move with the impacter, and thespring will be compressed. The depth and shape of the grooves are suchthat due to the limited axial movement of the impacter, the balls willbe forced to leave the shallower grooves 5, 5, etc., but remain in thedeeper grooves I, I, etc., moving with the imtorque block will beaccelerated. However, as soon as the balls have been rotated to aposition opposite the neXt forward set of grooves 5, 5, etc., they willbe rammed into these grooves by the force of the spring i8 assisted bythe centrifugal force of the balls due to their rotation. The impact ofthe balls on the leading ments and extending in a direction having aradially outward component, all said deeper not more than 90 degrees sothat upon sufficient pressure being exerted on a rolling element caughtin the end of one of said other grooves edges of grooves 5, 5, etc. willrotate the torque block and therefore the nut I2.

The above cycle of events will be continuously repeated at a rateproportional to the speed of rotation of the drive shaft I6, until thenut is loose enough to turn with the torque block without impacts, afterwhich the pressure of the spring I8 will hold the balls in the grooves5, 5. etc., and all the elements will rotate together at the speed ofshaft I6.

If it is desired to turn nut I2 in the direction opposite to that abovedescribed, the operator may simply reverse the motor, and the abovedescribed cycle of events will take place just as before, except in theproper order for reverse rotation of the nut.

It is to be understood that the above devices represent but two forms ofthe invention which includes all other forms and obvious modificationsWithin the scope of the claims appended hereto. A third form is shownand claimed in Patent No. 2,399,251 issued April 30, 1946, as a divisionof this patent.

The invention described herein may be manufactured and used by or forthe Government of the United States for governmental purposes withoutthe payment to me of any royalties thereon or therefor.

What I claim is:

1. In a reversible variable speed power tool for turning, tightening andloosening parts; a coupling between the driving and driven memberscomprising a pair of aligned rotatable members attached respectivelythereto and having closely adjacent opposed circumferential surfaces,there being a similar seriesv of grooves equally spaced around thecircumference of each of said surfaces,van anti-friction element foreach of the grooves in one of said surfaces, the latter grooves being ofa depth sufcient to contain the anti-friction elements, the othergrooves being slightly less than half of such depth, said deeper grooveshaving sharp edges for simultaneously snapping all the elements out oftheir shallow grooves in cooperation with the opposed end edges thereof.

2. In a reversible variable speed power tool for turning, tightening andloosening parts, a coupling between the driving and driven meanscomprising a pair of aligned rotatable members attached respectivelythereto and having closely adjacentl opposed surfe/ces of revolution,there being similar series of grooves equally spaced around thecircumference of each of said surfaces, a rolling element for each ofthe grooves in one of said surfaces, the latter grooves having a depthextending in a direction having a radially inward component, the othergrooves having angular sides which sides are also angular to theadjacent sides of the next adjacent grooves and are slightly less thanhalf the depth equivalent to the diameter of said rolling eleby the edgeat the end of the .opposed groove, the said rolling element will becaught invshear between the sharp edge of said other groove and theangular side of said opposed groove and thereby will be snapped out ofthe said other groove into the opposed one and thus the two surfaceswill move relative to each other after imparting a sharp impact to thedriven member.

3. The combination of claim 2 wherein the surfaces of revolution areparallel to the axis of rotation.

4. The combination of claim 2 wherein the surfaces of revolution areparallel to the axis of rotation and the groovesin the inner member aredeep enough to contain the rolling elements.

5. In a reversible variable speed power tool for turning, tightening andloosening parts; a coupling between the driving and driven memberscomprising a pair of aligned rotatable members attached respectivelythereto and having closely' adjacent opposed circumferential spr faces,there being a similar series of grooves equally spaced around thecircumference of each of said surfaces, an anti-friction element foreach of the grooves in one of said surfaces. the latter grooves being ofa slightly greater depth than the diameter of the anti-frictionelements, the other grooves being of a depth slightly less than theradius of said elements, all of said latter grooves having sharp edgesat their ends.

6. In a reversible speed power tool for turning, tightening andloosening'parts; a coupling between the driving and driven memberscomprising a pair of aligned rotatable members attached respectivelythereto and having closely adjacent opposed surfaces of revolution,ythere being a similar series of grooves equally spaced around thecircumferenceof each of said surfaces, a rolling element for each of thegrooves in one of said surfaces, the latter grooves being of a depthsufllcient to contain said rolling'elements.

the other grooves being slightly less than half of such depth, all saidlatter grooves having sharp edges at their ends.

Y CARL WESLEY PORTER.

REFERENCES CITED The following references are of record in the ille ofthis patent:

UNI'I'ED STATES PATENTS

